The present invention is directed to control devices for bicycle transmissions and, more particularly, to a bicycle derailleur that includes a derailleur cable router for changing the direction of a derailleur cable.
U.S. Pat. No. 5,624,334 discloses one type of derailleur cable router for changing the direction of a derailleur cable having a cable housing surrounding at least a portion of the derailleur cable. In the derailleur cable router disclosed in that patent, a pulley is mounted to a frame for rotation around a pulley axis. The frame includes a first leg extending radially from the pulley axis for supporting the cable housing and a second leg extending radially from the pulley axis for supporting a derailleur interface member. The derailleur interface member slidingly and detachably engages a cable feed formed on the base member of the derailleur at the rear of the derailleur so that the cable router can deflect in response to external forces.
Because the derailleur cable router is an add-on part coupled to the rear of the derailleur, the derailleur cable router forms a relatively large appendage which increases the bulk of the derailleur and also creates more surface area that can be subjected to undesirable external forces. Also, since the derailleur cable router is detachably coupled to the derailleur, there is a risk that the derailleur cable router can become dislocated from the derailleur when a sudden force is applied to the pulley or frame. Such dislocation also could occur as a result of rotation of the derailleur during operation of the derailleur.
Thus, it is desirable to make a derailleur cable router that is more compact to minimize the surface area that could be subjected to undesirable external forces. It is also desirable to make a derailleur cable router that can accommodate lateral deflection caused by external forces applied to the cable router as well as deflection caused by rotation of the derailleur during operation of the derailleur, all without dislocating from the derailleur.
The present invention is directed to a derailleur cable guide router which is very compact and which accommodates lateral deflection caused by external forces applied to the cable router as well as deflection caused by rotation of the derailleur during operation of the derailleur, all without dislocating from the derailleur. In one embodiment of the present invention, a derailleur cable router is provided for changing the direction of a derailleur cable having a cable housing surrounding at least a portion of the derailleur cable. The derailleur cable router includes a base member, a pulley mounted on the base member for rotation around a pulley axis, and a housing support movably supported on the base member. The housing support pivots relative to the pulley around a first axis and a second axis, wherein the first axis is different from the second axis.
In a more specific embodiment, the first axis extends in a direction substantially parallel to the pulley axis, and the second axis extends in a direction substantially perpendicular to the pulley axis. Thus, rotation of the housing support around the first axis accommodates deflection caused by rotation of the derailleur during operation of the derailleur, and rotation of the housing support around the second axis accommodates lateral deflection caused by external forces applied to the cable router.
If the base member of the derailleur cable router also functions as the base member for the derailleur, then the resulting structure is very compact and does not form a large appendage to the derailleur. In that case the pivoting housing support is all that is necessary to accommodate deflection caused by rotation of the derailleur during operation of the derailleur and lateral deflection caused by external forces applied to the cable router.